Exhibit 23.3 Consent of Deloitte & Touche LLP, Independent Auditors EXHIBIT 23.3 INDEPENDENT AUDITORS' CONSENT We consent to the incorporation by reference in this Registration Statement of Ligand Pharmaceuticals Incorporated on Form S-8 of our report dated February 23, 2001, appearing in the Annual Report on Form 10-K of Ligand Pharmaceuticals Incorporated for the year ended December 31, 2000. /s/ Deloitte & Touche LLP San Diego, California July 27, 2001